1. Field of the Invention
The present invention relates generally to methods for fabricating read sensors for magnetic heads, and more particularly to methods for reducing the magnetic read track width of the sensor.
2. Description of the Prior Art
Magnetic heads for hard disk drives typically contain a read head element for reading magnetic data bits from the magnetic media disk, and a write head for writing magnetic data bits onto the magnetic media disk. Focusing on the read head element, a plurality of sensor layers are deposited across the surface of the wafer. Thereafter, to establish a magnetic read track width for the sensor, a photolithographic process is conducted in which an ion milling mask is photolighographically fabricated above the sensor layers. An ion milling process is then conducted in which unmasked portions of the sensor layers are removed while the sensor layers that are protected by the mask remain. Further read sensor and magnetic head structures are subsequently fabricated, however the magnetic read track width of the sensor is determined in the ion milling process.
In order to achieve greater areal data storage density within the magnetic media, magnetic data bits are written in increasingly smaller sizes, and the magnetic read sensors of the magnetic heads must therefore be fabricated with a reduced magnetic read track width to properly read the smaller sized data bits. In prior art attempts of fabricate a magnetic head with a narrower read track width sensor, shorter wavelength photolithographic exposure energy is utilized to create the ion milling mask. A problem that is encountered in this process is that the photoresist layer must be thinner than desired in order to be properly exposed by the shorter wavelength energy to create the ion milling mask. However, the thinner photoresist mask is not adequately robust to survive the subsequent sensor layer ion milling step. The present invention provides a fabrication method for creating a more robust ion milling mask which avoids these problems.